Micro Tunneling Machine

ABSTRACT

The present disclosure relates to a tunneling apparatus including a drill head including a main body and a steering member that is movable relative to the main body. The tunneling apparatus includes a steering target attached to the main body. The tunneling apparatus also includes a camera mounted within the main body. Further, the tunneling apparatus includes a shell position indicator mounted to the steering member in the field of view of the camera. The shell position indicator is adapted to indicate relative movement between the target and the shell position indicator. Additionally, the position indicator frames the target when no relative movement between the target and shell position indicator is indicated.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/733,639, filed Dec. 5, 2012, which application is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates generally to trenchless drilling equipment. More particularly, the present disclosure relates to tunneling equipment capable of maintaining a precise grade and line.

BACKGROUND

Modern installation techniques provide for the underground installation of services required for community infrastructure. Sewage, water, electricity, gas and telecommunication services are increasingly being placed underground for improved safety and to create more visually pleasing surroundings that are not cluttered with visible services.

One method for installing underground services involves excavating an open trench. However, this process is time consuming and is not practical in areas supporting existing construction. Other methods for installing underground services involve boring a horizontal underground hole. However, most underground drilling operations are relatively inaccurate and unsuitable for applications on grade and on line.

U.S. Pat. Publication No. 2010/0230171 discloses a micro-tunneling system and apparatus capable of boring and reaming an underground micro-tunnel at precise grade and line. While this system represents a significant advance over most prior art systems, further enhancements can be utilized to achieve even better performance.

SUMMARY

One aspect of the present disclosure relates to a tunneling apparatus having a shell position indicator that moves in response to relative movement between the main body of the drill head and the steering member of the drill head. In certain embodiments the shell position indicator is in the field of view of the camera and frames a target when no relative movement between the target and shell position indicator is indicated. In certain embodiments, the shell position can include protrusions that align with predetermined portions of the target.

Another aspect of the present disclosure relates to a tunneling apparatus having a camera lens cleaning system in order to facilitate effective steering. In certain embodiments the system can include a fluid pump for pumping drilling fluid to the drill head; a camera lens cleaner in fluid communication with the fluid pump for cleaning the camera lens; and wherein the fluid expelled by camera lens cleaner is controlled by varying fluid pump flow.

Another aspect of the present disclosure relates to a tunneling apparatus having a hydraulic purge system. The system includes a plurality of steering hydraulic lines and a plurality of bleed ports in fluid communication with a plurality of bleed valves. Further, in certain embodiments the system includes a means for opening the bleed valves so that fluid contained in the steering hydraulic lines travels back into a hydraulic fluid reservoir when a hydraulic pump is in operation.

A variety of additional aspects will be set forth in the description that follows. The aspects can relate to individual features and to combinations of features. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the broad inventive concepts upon which the embodiments disclosed herein are based.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic depiction of a tunneling apparatus having features in accordance with the principles of the present disclosure;

FIG. 2 is a perspective view showing a male end of a pipe section suitable for use with the tunneling apparatus schematically depicted at FIG. 1;

FIG. 3 is a perspective view showing a female end of the pipe section of FIG. 2;

FIG. 4 is a side view of a drill head suitable for use with the tunneling apparatus of FIG. 1;

FIG. 5 is a side, cross-sectional view of the drill head of FIG. 4 with the drill head being cut by a vertical cross-sectional plane that bisects the drill head along section line C;

FIG. 6 is a cross-sectional view taken along section line D of FIG. 4;

FIG. 7 is a cross-sectional view taken along section line A of FIG. 4;

FIG. 8 is a schematic view of a hydraulic piston cylinder;

FIG. 9 is a hydraulic circuit diagram of the hydraulic purge system suitable for use with the tunneling apparatus of FIG. 1;

FIG. 10 is a side view of the drill head of FIG. 4 with portions of the outer shell removed to show the camera and steering indicator;

FIG. 11 is a cross-sectional view taken along section line B of FIG. 4;

FIG. 12 is a side view of the drill head of FIG. 4 with portions of the outer shell removed to show the camera lens cleaning system; and

FIG. 13 shows a side view of the camera and drilling fluid wash line.

DETAILED DESCRIPTION

FIG. 1 shows a tunneling apparatus 20 having features in accordance with the principles of the present disclosure. Generally, the apparatus 20 includes a plurality of pipe sections 22 that are coupled together in an end-to-end relationship to form a drill string 24. Each of the pipe sections 22 includes a drive shaft 26 rotatably mounted in an outer casing assembly 28. A drill head 30 is mounted at a distal end of the drill string 24 while a drive unit 32 is located at a proximal end of the drill string 24. The drive unit 32 includes a torque driver adapted to apply torque to the drill string 24 and an axial driver for applying thrust or pull-back force to the drill string 24. Thrust or pull-back force from the drive unit 32 is transferred between the proximal end to the distal end of the drill string 24 by the outer casing assemblies 28 of the pipe sections 22. Torque is transferred from the proximal end of the drill string 24 to the distal end of the drill string 24 by the drive shafts 26 of the pipe sections 22 which rotate relative to the casing assemblies 28. The torque from the drive unit 32 is transferred through the apparatus 20 by the drive shafts 26 and ultimately is used to rotate a cutting unit 34 of the drill head 30.

The pipe sections 22 can also be referred to as drill rods, drill stems or drill members. The pipe sections are typically used to form an underground bore, and then are removed from the underground bore when product (e.g., piping) is installed in the bore.

The drill head 30 of the drilling apparatus 20 can include a drive stem 46 rotatably mounted within a main body 38 of the drill head 30. A distal end of the drive stem 46 is configured to transfer torque to the cutting unit 34. A proximal end of the drive stem 46 couples to the drive shaft 26 of the distal-most pipe section 22 such that torque is transferred from the drive shafts 26 to the drive stem 46. In this way, the drive stem 46 functions as the last leg for transferring torque from the drive unit 32 to the cutting unit 34. The outer casing assemblies 28 transfer thrust and/or pull back force to the main body 38 of the drill head. The drill head 30 preferably includes bearings (e.g., axial/thrust bearings and radial bearings) that allow the drive stem 46 to rotate relative to the main body 38 and also allow thrust or pull-back force to be transferred from the main body 38 through the drive stem 46 to the cutting unit 34.

In certain embodiments, the tunneling apparatus 20 is used to form underground bores at precise grades. For example, the tunneling apparatus 20 can be used in the installation of underground pipe installed at a precise grade. In some embodiments, the tunneling apparatus 20 can be used to install underground pipe or other product having an outer diameter less than 600 mm or less than 300 mm.

It is preferred for the tunneling apparatus 20 to include a steering arrangement adapted for maintaining the bore being drilled by the tunneling apparatus 20 at a precise grade and line. For example, referring to FIG. 1, the drill head 30 includes a steering shell 36 mounted over the main body 38 of the drill head 30. Steering of the tunneling apparatus 20 is accomplished by generating radial or pivot movement between the steering shell 36 and the main body 38 (e.g., with radially oriented pistons). Radial steering forces for steering the drill head 30 are transferred between the shell 36 and the main body 38. From the main body 38, the radial steering forces are transferred through the drive stem 46 to the cutting unit 34.

Steering of the tunneling apparatus 20 is preferably conducted in combination with a guidance system used to ensure the drill string 24 proceeds along a precise grade and line. For example, as shown at FIG. 1, the guidance system includes a laser 40 that directs a laser beam 42 through a continuous axially extending air passage 43 defined by the outer casing assemblies 28 of the pipe sections 22 to a target 44 located adjacent the drill head 30.

The tunneling apparatus 20 also includes an electronic controller 50 (e.g., a computer or other processing device) linked to a user interface 52 and a monitor 54. The user interface 52 can include a keyboard, joystick, mouse or other interface device. The controller 50 can also interface with a camera 60 such as a video camera that is used as part of the steering system. For example, the camera 60 can generate images of the location where the laser hits the target 44. It will be appreciated that the camera 60 can be mounted within the drill head 30 or can be mounted outside the tunneling apparatus 20 (e.g., adjacent the laser). If the camera 60 is mounted at the drill head 30, data cable can be run from the camera through a passage that runs from the distal end to the proximal end of the drill string 24 and is defined by the outer casing assemblies 28 of the pipe sections 22. In still other embodiments, the tunneling apparatus 20 may include wireless technology that allows the controller to remotely communicate with the down-hole camera 60. The drill head can include a sonde 85 that is part of a locating/tracking system. The sonde 85 can generate a wireless electromagnetic signal that travels upwards through the ground and is detected/sensed by an above-ground locator. An example of a sonde is disclosed in U.S. Pat. No. 5,155,442 and U.S. Pat. No. 5,337,002 which are hereby incorporated herein by reference in their entirety. Further, in other embodiments the tunneling apparatus 20 may include orientation sensing devices (e.g., accelerometer and/or gyroscope) that are used as part of the steering system. The orientation sensing devices can be used to sense an inclination angle of the main body 38 of the drill head 30. Such technology may interface with the controller 50 through a wired or wireless connection. In certain embodiments, the controller 50 may provide a graphical read out of the drill head position on the monitor 54.

During steering of the tunneling apparatus 20, the operator can view the camera-generated image showing the location of the laser beam 42 on the target 44 via the monitor 54. Based on where the laser beam 42 hits the target 44, the operator can determine which direction to steer the apparatus to maintain a desired line and grade established by the laser beam 42. The operator steers the drill string 24 by using the user interface to cause a shell driver 39 to modify the relative radial position of the steering shell 36 and the main body 38 of the drill head 30. For example, if it is desired to steer the drill string 24 upwardly, a downward force can be applied to the steering shell 36 which forces the main body 38 and the cutting unit 34 upwardly causing the drill string to turn upwardly as the drill string 24 is thrust axially in a forward/distal direction. Similarly, if it is desired to steer downwardly, an upward force can be applied to the steering shell 36 which forces the main body 38 and the cutting unit 34 downwardly causing the drill string 24 to be steered downwardly as the drill string 24 is thrust axially in a forward/distal direction.

The radial steering forces are applied to the steering shell 36 by a plurality of radial pistons that are selectively radially extended and radially retracted relative to a central longitudinal axis 74 of the drill string through operation of a hydraulic pump and/or valving 48. The hydraulic pump and/or valving 48 are in fluid communication with a hydraulic fluid reservoir 56. The hydraulic pump and/or valving 48 are controlled by the controller 50 based on input from the user interface. In one embodiment, the hydraulic pump and/or the valving 48 are located outside the hole being bored and hydraulic fluid lines are routed from pump/valving 48 to the radial pistons via a passage that runs from the distal end to the proximal end of the drill string 24 and is defined within the outer casing assemblies 28 of the pipe sections 22. In still other embodiments, the tunneling apparatus 20 may include wireless technology that allows the controller to remotely control the hydraulic pump and/or valving 48 within the drill head 30.

To assist in drilling, the tunneling apparatus 20 can also include a fluid pump 63 for forcing drilling fluid from the proximal end to the distal end of the drill string 24. In certain embodiments, the drilling fluid can be pumped through a central passage 45 defined through the drive shafts 26. The central passage 45 defined through the drive shafts 26 can be in fluid communication with a plurality of fluid delivery ports provided at the cutting unit 34 such that the drilling fluid is readily provided at a cutting face of the cutting unit 34.

Various modifications and alterations of this disclosure will become apparent to those skilled in the art without departing from the scope and spirit of this disclosure, and it should be understood that the scope of this disclosure is not to be unduly limited to the illustrative embodiments set forth herein.

Referring now to FIGS. 2 and 3, perspective views showing a male and female ends of a pipe section suitable for use with the tunneling apparatus 20 are shown. The pipe section 22 is elongated along a central axis 64 and includes a male end 66 and an oppositely positioned female end 68. When a plurality of the pipe sections 22 are strung together, the female ends 68 are coupled to the mail male ends 66 of the adjacent pipe sections 22. The outer casing assembly 28 of the depicted pipe section 22 includes end plates 70 positioned at the male and female ends 66, 68. The outer casing assembly 28 also includes an outer shell 72 that extends from the male end 66 to the female end 68. The outer shell 72 is generally cylindrical and defines an outer diameter of the pipe section 22. In a preferred embodiment, the outer shell 72 is configured to provide support to a bore being drilled to prevent the bore from collapsing during the drilling process.

Referring now to FIG. 4, is a side view of a drill head 30 suitable for use with the tunneling apparatus 20. The drill head 30 is elongated on a central longitudinal axis 74 that extends from a proximal end 76 to a distal end 78 of the drill head 30. A flexible skirt 62 extends from the proximal end 76 of the shell 36 to the main body 38 of the distal section 78. The flexible skirt 62 prevents debris from getting under the shell 36. The proximal end 76 of the drill head 30 is configured to be mechanically coupled to the distal end of the distal-most pipe section 22 of the drill string 24. In the depicted embodiment, the axis 74 of the drill head 30 is coaxially aligned with the overall central axis defined by the pipe sections 22 of the drill string 24 when the proximal end 76 coupled to the distal end of the distal-most pipe section 22.

The cutting unit 34 and the steering shell 36 are mounted at the distal end 78 of the drill head 30. The main body 38 of the drill head 30 includes a cylindrical outer cover 80 that extends generally from the steering shell 36 to the proximal end 76 of the drill head 30. The steering shell 36 has a larger outer diameter than the outer diameter of the cover 80.

Referring now to FIG. 5, showing section views of the drill head 30. Located at the distal end 78 of the drill head 30, the steering shell has both proximal and distal ends 86, 88. The distal section 88 of the steering shell 36 includes a drive mechanism for providing the motive force for pivoting the shell relative to the main body 38 of the drill head 30 and the steering shell 36. The distal section of the steering shell 88 also includes a pivot structure 90 that allows the shell 36 to pivot universally relative to the main body 38 of the distal section 88. The drive mechanism is controlled by four of radial pistons 82 mounted in cylinders 83 defined by a module of the main body 38. As shown in FIG. 6, each cylinder is connected to a steering manifold 100, located in the proximal end 76 of the drill head 30. The steering manifold 100 is also in fluid communication with a hydraulic fluid pump 48 and hydraulic fluid reservoir 56. Further, the drill head 30 also includes a bleed valve 98 located at the proximal end 76. The bleed valve 98 is connected to each cylinder 83 a-83 d via a series of hydraulic fluid lines. In some embodiments the drill head 30 may include a sonde 85. The sonde may transmit electromagnetic signals upwardly through the ground to allow for the position of the drill head 30 to be determined by a locator such as a hand-held locator.

Referring now to FIG. 7, the pistons 82 include four radial pistons that are offset from one another by 90°. The pistons 82 can be selectively extended and retracted to offset the steering shell 36 a relative distance from the main body 38. The pistons 82 are extended and retracted by fluid pressure (e.g., hydraulic fluid pressure) provided to the piston cylinders 83 a-83 d through axial hydraulic fluid passages 84 a-84 d. Fluid pressure is controlled by a hydraulic fluid pump 48 and hydraulic fluid is supplied to the piston cylinders 83 a-83 d via a plurality of hydraulic fluid lines (e.g. hoses). To pivot the nose of the shell 36 downwardly, the two upper pistons 82 are extended while the two lower pistons 82 are refracted. Alternatively, to pivot the nose of the shell 36 upwardly, the two upper pistons 82 are retracted and the two lower pistons 82 are extended. To pivot the nose of the shell 36 leftwardly, the two rightward pistons 82 are extended and the two leftward pistons 82 are retracted. To pivot the nose of the shell 36 rightwardly, the two leftward pistons 82 are extended and the two rightward pistons 82 are retracted. A steering indicator 92 is utilized to sense the relative movement between the steering shell 36 and main body 38 as the pistons 82 are operated during steering.

During normal operation of the tunneling apparatus 20, hydraulic fluid lines and fittings often need to be replaced as part of regular maintenance. When a hydraulic fluid line is replaced, the new line is typically full of air rather than hydraulic fluid. When air is present in a hydraulic system energy is wasted by compressing the air in the system rather of compressing the hydraulic fluid. When energy is wasted it lowers the efficiency of the overall hydraulic system making the system less effective. To remedy this issue the hydraulic system is bled, or purged, of the air trapped in the hydraulic lines whenever a hydraulic line is replaced. In the present invention each piston cylinder 83 a-83 d is fitted with a bleed port 94. The bleed ports 94 allow for air to be removed from the system and transferred into a hydraulic fluid reservoir 56. The bleed ports 94 are plugged when the system is not being bled.

Referring now to FIG. 8, showing a schematic of one of the cylinders. The cylinders have a stepped bore of which two separate diameters D1 and D2 are created. Both D1 and D2 are larger than a diameter D3 of the piston 82. D1 is of a size to ensure a seal with the piston and the inner walls of the cylinder. D2 is a diameter slightly greater than D1 and allows hydraulic fluid within the cylinder to flow around the piston regardless of the piston's position within the cylinder. When the bleed port 94 is opened, fluid flows through the cylinder without activating and moving the piston 82. Hydraulic fluid enters the cylinder via the inlet port 96 and can exit the cylinder by either flowing back out of the inlet port 96 or through the bleed port 94 when the bleed port 94 is opened. In other embodiments a cylinder with a single diameter may be used. In such an embodiment the bleed port can be located at the bottom the cylinder next to the inlet port, therefore eliminating the need to step the cylinder.

FIG. 9 shows a hydraulic circuit diagram of a hydraulic purge system in the accordance with the principles of the present disclosure. Each cylinder 83 a-83 d is operated as a pair with the cylinder located 180 degrees away. For instance, when 83 a extends its respective piston 82, 83 c retracts its respective piston 82. Each cylinder 83 a-83 d is connected to a bleed valve 98 via hydraulic bleed flow lines 200 a-200 d that are connected to each cylinder's bleed port 94. When the bleed valve 98 is open, the bleed ports 94 of the cylinder 83 a, 83 c are fluidly connected and the bleed ports 94 of cylinder 83 b, 83 d are fluidly connected.

Additionally, each cylinder is also connected to the steering manifold 100 via hydraulic fluid flow lines 202 a-202 d that are connected to the cylinders' axial hydraulic fluid ports 84 a-84 d. The steering manifold 100 contains a plurality of steering valves 112 that correspond and connect to the cylinders 83 a-83 d. The steering manifold 100 is connected to a hydraulic fluid pump 48 and a hydraulic fluid reservoir 56.

Movement of the cylinders 83 a, 83 c is controlled by one of the steering valves 112 and movement of cylinders 83 b, 83 d is controlled by another steering valve 112. The steering valves 112 have three positions: a left, a neutral, and a right position. The steering valves 112 are shown in neutral position in FIG. 9, where no fluid communication exists between any of the cylinders, pump, or reservoir. When one of the cylinders 83 a, 83 c is connected to the hydraulic pump 48 by their corresponding steering valve 112, the other of the cylinders 83 a, 83 c is connected to the reservoir 56 by their correspond steering valve 112. For instance, when the corresponding steering valve 112 is moved all the way to the right, cylinder 83 a is connected to the reservoir 56 and cylinder 83 c is connected to the hydraulic pump 48. When the corresponding steering valve 112 is moved all the way to the left, cylinder 83 a is connected to the hydraulic pump 48 and cylinder 83 c is connected to the reservoir 56. Similarly, when one of the cylinders 83 b, 83 d is connected to the hydraulic pump 48 by their corresponding steering valve 112, the other of the cylinders 83 b, 83 d is connected to the reservoir 56 by their corresponding steering valve 112. For instance, when the corresponding steering valve 112 is moved all the way to the right, cylinder 83 d is connected to the reservoir 56 and cylinder 83 b is connected to the hydraulic pump 48. When the corresponding steering valve 112 is moved all the way to the left, cylinder 83 d is connected to the hydraulic pump 48 and cylinder 83 b is connected to the reservoir 56.

In one example, during normal operation of the hydraulic steering system, hydraulic fluid flows from the hydraulic fluid pump 48 to the steering manifold 100. The fluid then travels to two of the four cylinders 83 a-83 d to extend two of their pistons to accomplish a steering change. At this same time, the steering valves 112 corresponding with the two remaining non-actuated pistons is opened and fluid is allowed to flow from the cylinders to the hydraulic reservoir 56. In one example, to steer the drill head 30 to the right cylinders 83 a and 83 b would be connected to the hydraulic fluid pump 48 by way of their corresponding steering valve 112 so that their two respective pistons 82 are activated. In certain embodiments the pressure from the steering shell on the non-actuated pistons will force the hydraulic fluid existing in the non-actuated piston cylinder back to the hydraulic fluid reservoir 56 and cause the non-actuated pistons to retract completely. In other embodiments, a closed-loop system may be used in which a vacuum is created to remove fluid from the opposite cylinder to aid retraction of the piston. In other embodiments, instead of paired cylinders, a two cylinder, four piston system may be used. Each cylinder in the two cylinder system, would each contain a cross member. The cross member in each cylinder would be displaced a distance in the direction towards the cylinder in which hydraulic pressure is increased on. Such a system could be a closed loop system containing only a certain amount of fluid.

The bleed valve 98 is movable between open and closed position. When the bleed valve 98 is in the open position, bleed ports 94 of cylinders 83 a, 83 c are fluidly connected to one another and bleed ports 94 of cylinders 83 b, 83 d are fluidly connected together. When the bleed valve 98 is in the closed position the bleed ports 84 of the cylinders 83 a, 83 c are not fluidly connected through the bleed valve 98 and the bleed ports 94 of the cylinders 83 b, 83 d are not fluidly connected through the bleed valve 98.

After a hydraulic fluid line or fitting is replaced in the system the system is then purged to remove air. To accomplish a purge, or bleed, the bleed valve 98 is manually opened. In other embodiments the bleed valve may be operated electronically via a controller. Once the bleed valve 98 is opened the bleed ports 94 are also opened. Hydraulic fluid is then pumped to cylinders 83 b and 83 c. It will be appreciated fluid may alternatively be pumped to any two adjacent cylinders as this scenario is merely an example to illustrate the operating characteristics of the system. Fluid enters cylinders 83 b and 83 c via axial hydraulic fluid passages 84 b and 84 c and inlet ports 96. The hydraulic fluid then exits each cylinder 83 b, 83 c by way of the bleed ports 94 and flows back to the bleed valve 98. Once at the bleed valve 98, the hydraulic fluid is then routed to the opposite cylinders 83 a and 83 d. For instance the fluid that came from the cylinder 83 c is routed to its paired cylinder 83 a. The hydraulic fluid travels back to cylinders 83 a, 83 d, and enters the cylinders via the bleed ports 94. The hydraulic fluid then exits the cylinders via the inlet port 96 and axial hydraulic fluid passages 84 a, 84 d. Finally, the fluid flows back to the steering manifold and then to the hydraulic fluid reservoir 56. This process effectively removes any air trapped in the any hydraulic fluid lines.

Once the system is purged the bleed valve 98 is closed and system is prepared to resume normal drilling behavior. In addition to the hydraulic purge system the steering system also includes a steering indicator. As the pistons move the steering shell to facilitate steering the operator must receive feedback from the drill head to steer the drill head in a desired direction. In certain embodiments a steering indicator may be used to inform the operator the orientation of the steering shell. FIG. 10 and FIG. 11 show that the steering indicator 100 is mounted to the steering shell 36 via a mounting arm 103. During steering, the pistons 82 cause relative radial movement between the steering shell 36 and the main body 38. When this relative radial movement occurs, the position indicator 100 also changes position relative to the main body 38 to which the target 44 is attached. For example, the position indicator 100, in response to relative radial movement between the steering shell 36 and main body 38, will offset a certain direction. The steering indicator mounting arm 103 is positioned to pass through a passage 102 created between the steering shell 36 and the main body 38 and through an opening in a side wall of the main body 38. The steering indicator 100 includes two framing arms 101 a, 101 b that hang down into a cavity of the main body 38 and frame the target 44 when no relative movement between the target 44 and steering indicator 100 is indicated (i.e. when the shell is concentric with the main body). Each arm 101 a, 101 b includes a protrusion structure 104 that is aligned with a portion of the target 44 when viewing the steering indicator from the proximal end 76 of the drill head 30 via the camera 60. The protrusions 104 align with a center target 44 when the steering shell 36 is in a straight orientation (i.e. when the shell is concentric/coaxial with the main body 38). When the nose of the steering shell 36 pivots down, the protrusions 104 move up relative to the target 44. When the nose of the steering shell 36 pivots up, the protrusions 104 move down relative to the target 44. When the nose of the steering shell 36 pivots left, the protrusions 104 move right relative to the target 104. When the nose of the steering shell 36 pivots left, the protrusions 104 move right relative to the target 104.

The operator is informed of the position of the steering indicator 100 via a display that shows the view of the camera 60. The protrusion structures 104 are located on the framing arms 101 a, 101 b that allow for the operator to adjust the pistons 82 depending on the location of the protrusions 104 with respect to the target 44 and the desired trajectory of the steering shell 36.

The target 44 of the tunneling apparatus 20 is mounted to a wall in the distal end of the main body. The target 44 preferably axially aligns with the air passage 43. In this way, the laser 42 can be directed through the air passage 43 to reach the target 44. The camera 60 for viewing the target 44 is preferably mounted at a region 105 located axially between the cutting unit 34 and the proximal end 76 of the drill head 30. The camera 60 is preferably oriented to view through the air passage 43 such that the camera 60 can generate an image of the target 44. In addition to generating images of the target 44, the camera also generates images of the steering position indicator 100 mounted to the steering shell 36. The position indicator partially overlaps the air passage 43 so as to be visible by the camera (i.e., the position indicator are within the field of view of the camera).

An operator viewing the position indicator 100 while steering the drill string 24 can confirm at least two things. First, movement of the position indicator 100 indicates that the relative movement between the shell 36 and the main body 38 is indeed occurring (i.e., the steering shell 36 is not jammed relative to the main body 38 of the drill head 30). Second, by noting the position of the protrusions 104 relative to the target 44 at a given time, the operator can confirm that the actual relative position between the steering shell 36 and the main body 38 of the drill head 30 matches the desired relative position between the steering shell 36 and the main body 38 of the drill head 30.

During the drill process the camera 60 can become dirty which decreases the visibility of the steering indicator via the camera feed. FIG. 12 shows a section view of the drill head 30 specifically showing the camera lens cleaning system. There is a need to keep the camera 60 clean in order to ensure that the operator may be able to actively steer the drill head 30 depending on the movement and location of the steering indicator 100 relative to the target 44. Manually removing the drill head 30 from the ground during a bore to clean the camera lens is not only cumbersome but such an activity can stall a drilling job for an extended period of time. Drilling fluid may be used to clean and douse the camera lens to clean the camera lens 60 during drilling. A drilling fluid manifold 106 is located in the proximal end 76 of the drill head 30 and is used to allow the passage of drilling fluid from the drilling fluid pump 63 to the drill head 30. The drilling fluid manifold 106 includes a relief valve 108 that opens only when the drilling fluid pressure increases past a predetermined threshold. A drilling fluid wash line 110 is connected to the relief valve 108 and routed to the location of the camera 60 near the distal end 78 of the drill head 30 (e.g. as shown FIG. 13). The drilling fluid wash line 110 facilitates the flow of fluid from the relief valve 108 to the camera lens 60 to remove any debris located on the camera 60. If the operator desires to clean the camera 60 the drilling fluid pressure is momentarily increased past the predetermined threshold, effectively opening the relief valve 108 and allowing fluid to flow onto the camera 60. The camera lens cleaning system may be operated at any point in the drilling process when the drilling fluid pump 63 is running. In other embodiments a closed dedicated camera cleaning system may be used. Such a system could include a separate dedicated fluid pump that could be activated to pump fluid from a dedicated fluid supply to the camera lens for cleaning. Such an embodiment would eliminate the need of a relief valve and a threshold value. A closed system would not require the operator to increase the drilling fluid pressure but instead the operator could simply active the system by a button, switch or other means. 

What is claimed is:
 1. A tunneling apparatus comprising: a drill head including a main body and a steering member that is movable relative to the main body; a steering target attached to the main body; a camera mounted within the main body; a shell position indicator mounted to the steering member in the field of view of the camera, the shell position indicator being adapted to indicate relative movement between the target and the shell position indicator; and wherein the shell position indicator frames the target when no relative movement between the target and shell position indicator is indicated.
 2. The tunneling apparatus of claim 1, further comprising a cavity between the main body and the steering member where the shell position indicator is mounted to allow the shell position indicator to move freely.
 3. The tunneling apparatus of claim 1, wherein the position indicator includes protrusions that align with predetermined portions of the target when there no relative movement between the steering shell and the main body.
 4. A tunneling apparatus comprising: a drill head including a main body and a steering member, the steering member is movable relative to the main body, the drill head also including a camera to facilitate steering; a drilling fluid reservoir; a fluid pump for pumping drilling fluid to the drill head; a camera lens cleaner in fluid communication with the fluid pump for cleaning the camera lens; and wherein the fluid expelled by camera lens cleaner is controlled by varying fluid pump flow.
 5. The tunneling apparatus of claim 4, further comprising a fluid manifold located in the drill head to control of flow of drilling fluid to the drill head and camera lens cleaner.
 6. The tunneling apparatus of claim 4, further comprising a valve in fluid communication with the fluid pump and the camera lens cleaner wherein when the fluid pump operates at a predetermined pressure the valve is opened to supply fluid to the fluid lens cleaner.
 7. A tunneling apparatus comprising: a drill head having a movable shell; a series of cylinders for moving the shell, the cylinders including oppositely positioned first and second paired cylinders and third and fourth paired oppositely positioned cylinders, the first and second cylinders being configured such that a rod of the first cylinder retracts when a rod of the second cylinder extends and the rod of the second cylinder retracts when the rod of the first cylinder extends, the third and fourth cylinders being configured such that a rod of the third cylinder retracts when a rod of the fourth cylinder extends and the rod of the fourth cylinder retracts when the rod of the third cylinder extends; a first bleed line that fluidly connects the first and second paired cylinders; a second bleed line that fluidly connects the third and fourth paired cylinders; and a bleed valve for opening and closing the first and second bleed lines.
 8. The tunneling apparatus of claim 8, wherein the piston cylinders have two diameters, the first diameter is of a size so that the piston creates a seal with the wall of the cylinder, the second larger diameter is sized to allow oil to flow around the cylinder, regardless of the piston position, and into the bleed port when the hydraulic bleed valve is in the open position.
 9. A tunneling apparatus comprising: a hydraulic pump; a hydraulic reservoir; a set of four cylinders that each include a piston, the cylinders each having a first a second hydraulic fluid port, the piston in each cylinder being capable of extending and retracting by way of varying the hydraulic fluid pressure in the cylinder; a first control valve to control the movement of a first pair of cylinders; a second control valve to control the movement of a second pair of cylinders; a first steering hydraulic line that travels from the first control valve to a first cylinder to supply hydraulic fluid from the reservoir to the first cylinder; a second steering hydraulic line that travels from the first control valve to a second cylinder to supply hydraulic fluid from the reservoir to the second cylinder; a third steering hydraulic line that travels from the second control valve to a third cylinder to supply hydraulic fluid from the reservoir to the third cylinder; a fourth steering hydraulic line that travels from the second control valve to a fourth cylinder to supply hydraulic fluid from the reservoir to the fourth cylinder; a first bleed valve in fluid communication with the first cylinder, the hydraulic pump, and the hydraulic reservoir; a second bleed valve in fluid communication with the second cylinder, the hydraulic pump, and the hydraulic reservoir; a third bleed valve in fluid communication with the third cylinder, the hydraulic pump, and the hydraulic reservoir; a fourth bleed valve in fluid communication with the fourth cylinder, the hydraulic pump, and the hydraulic reservoir; a means for opening the first, second, third and fourth bleed valves so that fluid contained in the first, second, third or fourth steering hydraulic lines travels into the hydraulic fluid reservoir when the hydraulic pump is in operation.
 10. A tunneling apparatus comprising: a drill head including a main body and a steering member, the steering member is movable relative to the main body, the drill head also including a camera to facilitate steering; a camera lens cleaning fluid reservoir; a camera lens cleaning fluid pump for pumping cleaning fluid to the camera; a camera lens washing fluid line; a camera lens cleaning applicator in fluid communication with the camera lens cleaning fluid pump and the camera lens cleaning fluid reservoir for cleaning the camera lens; and wherein the fluid expelled by camera lens cleaning applicator is controlled by the camera lens cleaning fluid pump. 